A controlled substance is generally a drug or chemical whose manufacture, possession, or use is regulated by a government. Controlled substances are substances that are the subject of legislative control. This may include illegal drugs and prescription medications. In the United States for example, the Controlled Substances Act (or CSA) was passed by the 91st US Congress as Title II of the Comprehensive Drug Abuse Prevention and Control Act of 1970 and signed into law by President Richard Nixon. The CSA is the federal US drug policy under which the manufacture, importation, possession, use and distribution of controlled substances is regulated. In the US, the Drug Enforcement Administration (DEA) is responsible for suppressing illegal drug use and distribution by enforcing the Controlled Substances Act.
Section 812 of the Controlled Substances Act (21 U.S.C. § 801et seq.) (CSA) lists substances which were controlled in 1970 when the law was enacted. Since then, approximately 160 substances have been added, removed, or transferred from one schedule to another. The current official list of controlled substances can be found in section 1308 of the most recent issue of Title 21 Code of Federal Regulations (CFR) Part 1300 to end (21 CFR § 1308) and the final rules which were published in the Federal Register subsequent to the issuance of the CFR. The following link contains a full listing of the current federally Controlled Substances defined by the DEA, as of Jan. 5, 2018: https://www.deadiversion.usdoj.gov/schedules/orangebook/c_cs_alpha.pdf.
This list describes the basic or parent chemical and do not describe the salts, isomers and salts of isomers, esters, ethers and derivatives which may be controlled substances. These lists are intended as general references and are not comprehensive listings of all controlled substances. Please note that a substance need not be listed as a controlled substance to be treated as a Schedule I substance for criminal prosecution. A controlled substance analogue is a substance which is intended for human consumption and is structurally or pharmacologically substantially similar to or is represented as being similar to a Schedule I or Schedule II substance and is not an approved medication in the United States. (See 21 U.S.C. § 802(32)(A) for the definition of a controlled substance analogue and 21 U.S.C. § 813 for the schedule).
Drugs, substances, and certain chemicals used to make drugs are classified into five (5) distinct categories or schedules depending upon the drug's acceptable medical use and the drug's abuse or dependency potential. The abuse rate is a determinate factor in the scheduling of the drug; for example, Schedule I drugs are considered the most dangerous class of drugs with a high potential for abuse and potentially severe psychological and/or physical dependence. As the drug schedule changes—Schedule II, Schedule III, etc., so does the abuse potential—Schedule V drugs represents the least potential for abuse. A Listing of drugs and their schedule are located at Controlled Substance Act (CSA) Scheduling or CSA Scheduling by Alphabetical Order. These lists describe the basic or parent chemical and do not necessarily describe the salts, isomers and salts of isomers, esters, ethers and derivatives which may also be classified as controlled substances. These lists are intended as general references and are not comprehensive listings of all controlled substances.
Note that a substance need not be listed as a controlled substance to be treated as a Schedule I substance for criminal prosecution. A controlled substance analogue is a substance which is intended for human consumption and is structurally or pharmacologically substantially similar to or is represented as being similar to a Schedule I or Schedule II substance and is not an approved medication in the United States. (See 21 U.S.C. § 802(32)(A) for the definition of a controlled substance analogue and 21 U.S.C. § 813 for the schedule).